Telephone system.



W. HERRMANN & O. STRITTER.

TELEPHONE SYSTEM. APPucATloN HLED ocr. 25. ma.

Patend Mar. 19,1918

2 SHEETHHEET l.

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w. HERRMANN & o. STRITTER.

TELEPHONE SYSTEM. APPLlCATlON FILED OCT. 25. 1916.

Panmd 1181.19, 1918`I 2 SHEETS-SHEET 2- ,a ,rw

ATTU RN DAS 'Ill I Ill:

uNiTED s'rA'rns PATENT oFFioE.

WILL: HERRMANN, or' BEnLm-soHNEBEnG, AND o'r'ro srnr'r'rnn, or Lrorrrrmmnnn,

' GERMANY. a

TELEPHONE S YS'I'EM.

To al whom z'z= may concern:

Be it known that lI, WILL: HERRMANN, engineer, a subject of the Emperor of Germany, residing atandwhose post-oflice address is Colonnenstr. 29, Berlin-Schneberg, Germany, and I, OTTO STRITTER, engineer, a subject of the Emperor of Germany, residing at and whose post-oflice address is Papestr. 24, Lichtenrade, Germany, have invented certain new and useful Improvements in Telephone Systems; and we do hereby declare the following to be a, full, clear,

, and exactdescription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. ii

'Our invention refers to telephone, telegraph or electric signaling systems and more especially to a method of and apparatus for selecting and calling up stations which are connected to lines commonto all of them, by means of controllers moved step by step.

Systems of this kind generally use a controller which is moved until its hand reaches the sign or figure indicating the desired station. In this position of the hand the alarm of the desired station only is connected with the source of calling current of the calling station, this latter station thereupon efl'ecting the call by special means. This way of selecting and calling is, however, very cumbersome and takes too `long for the reason that, in selecting the desired station, care must be taken that the hand of the Controller at thecallingstation is not moved past the sign or figure of the desired i station; on the other hand in order to throw in'the calling signal on the desired station, a key or the like has to be operated. The inconvenience first spoken of is material in practice, as it happens `frequently that the proper indication on the Controller at the calling station is passed and-the movement of the controller has then to be continued for substantially a full turn in order to carryV the hand back again.

The present invention does away with these inconveniences in such a way that z merely the generator or another source of current at the calling station need'be cut in, while all the rest, such as stopping the selecting operation, throwing in the call signal on the desired station, and eventually carrying the controllers back to'their position of rest is elfected automatically inA the specification of Letters Patent. :Patent e d Mara19, 1918- Appncation med October 25,1916. seria11-r0.127,554. i

fications of such a systemV in a diagrammatic way; Fig. 3 'is a Vertical cross-section of a` Controller for use with the systems; Fig. 3a is a perspective view of the electromagnet;'Fig. 4 is a front view of the controller; and Fig. 5 is a detail, on an enlarged scale,

I of a modified form of shaft.`

Forthe sake of simplicity, there is shown in Fig. l a telephone system comprising but two stations A and'B, each provided `with a controlling device 8, such as is shown in Figs. 3 and 4. In this controlling device an electromagnet (Fig. 8a) Vcauses a shaft 'w to be rotated by a pawl and ratchet arrangenient, the contact Springs, f3 and a contact piece f' rigidly fiXe to said shaftbeing thus moved step by step simultaneously with a hand mounted in front of a dial z (Fig. 4). Forthe sake of simplicity, shaft w has been represented in Fig. 1 in two parts.

At each station, contact spring f' is fastened to shaft w in such manner that only the one at the station indicated by the hand 'z' contacts with pin fz. Each Controller 8 is provided with a detachable plug t adapted to be inserted optionally into vthe holes o which are provided in accordance with the number of sub-stations. f, in being moved, engages the inserted plug t, it is diseng'aged from its spring f3. The electrical connection of the movable Springs f, fs, f' is eifected, as shown in Fig. i3, by

brush collectors ft. o

In Fig. 1, 'w is a call alarm, ha telephone Whenever spring hook switch and c a generator.v The telephone hook switch his adapted to interrupt the circuit at the contact m whenever the receiver is lifted ofl', the transmitter being throwniiin at the same time. Upon rotati'ng i the generator o, the contact Springs k, Z are connected with contacts n, p, as a result of the fact that the handle is then'moved axially tozthe right for rotation and pulls the arms hand Z overwith it. i

The mode of operation of this device is as follows:

VVhene'ver the subscri-ber of sub-station A desires connection with sub-station- B, he inserts plug t in the hole 0 provided for' that sub-station, and turns the generator c. rfihe calling current then flows through the electromagnets c ofV allpthe sub-stations, through C31), Z, Z, f, fg, 2, k, n, 3, and thence through a to 4:, e, 5 and 6, of all sub-stations, bach through and 7 to c of the calling station. ln consequence thereof th'econtact Springs f, fg, f' of all sub-stations are simultaneously and equally moved step by step until the hands i reach B, the figure corresponding to sub-station that is being called. Spring fat the calling station A then engages the plug t inserted there and is ,disengaged from its spring fg. This causes the generator current to be cut oif from the electromagnets c of all the sub-st-ations and the controllers 8 to be stopped. However, as the contact spring f' at sub-station B is then in contactwith pin 7*'2, the calling current from generator 0 flows through the call alarm w of sub-station B by way of c, p, Z, Z, f and t, and then through the ground from sub-station A to B, where it passes through 7, f', 8, w, 9, m, 10 and 6, and thence back to generator c at sub-station A through b and 7 As soon as the subscriber of sub-station B has answered the call, by lifting the receiver off Vthehook switch h, the circuit at contact m is interrupted, thereby disconnecting his call alarm w and connecting in his transmitter and receiver. After the conversation is over, the controllers 8 inay be returned to their initial position in any suitable manner.

Another arrangement for selecting and calling a sub-station in accordance with the present invention is shown in Figs. 2, and 5. A groove V is provided in the shaft w of each controller 8, and a ball or roller g at the end of extension Q of pivoted lever u enters the end o of the groove when the shaft a: is momentarily retarded or braked with the two in registry. The openings 'v' of shafts m in the several sub-stations are disposed in such manner that only the one in the substation called stops in registry with the ball g. As long as the ball g runs in the groove, the contact at ll is closed. When the shaft has'been turned around once, the ball g leaves the groove at y and as soon as it has reached the surface of shaft w, the hand 'o' at the same time reaching its position of rest, the contact at 11 is opened again. For the remaining apparatus of the sub-stations CV and D',"the same reference letters as for the stations A, B have beenused in Fig. 2.

The, operation of this latter system `is similar to the one mentioned above;

In order for subscriber C to call subscriber D, plug t at sub-station O is inserted in the corresponding hole 0 and generator c is turned. The electromagnets of all substations are fed with current by way of c, 12,18, and let, where the current divides, one part passing through 15, c, 16, b and, 17 back to c of sub-station C, and the other part passing through 25, f, fa, 21k and 23 to a, and thence through the electromagnets of all sub-stations by way of 22, 21, fg, f 20, 19, c and 18, and back through Z) to sub-station C. Then the hand z' reaches the figure worresponding to sub-station D, spring f at sub-station (J engages the inserted plug at the same'tinie the ball or roller g of lever 'u in sub-station D registers with the end 0) of groove V. Plug 't disengages springs 7' and f, and in consequence thereof the controller 8 at sub-station D is cut out and stopped. T he ball or roller g at sub-station D is thereby permitted to enter the opening t' of the groove, which might notoccur if shaft x was turned without retardation at this position. However, the retardation `of controller 8 at sub-station D is only meinentary, electromagnet a 'at the calling station O not havinqi been cutiout. Upon rotating the generator c further, controller 8 at substation C continues itsinovement, spring f slides orer and again comes in contact with spring fg, thus restablishing the Circuit to electromagnet a of sub-station D; or, if desired, thelplug t at sub-station C may be in'oved to its initial position when the hand points to D, i'ihereby restablishing the circuit to electromagnet 8 of sub-station D by way of Springs f, fg of sub-station C, as before. In consequence thereof, the controller 8 at sub-station D is again moved along, the ballg then running in groove V andholding the Circuit of contact 28 closed. The alarm w at sub-station D is thus actuated by way of O, r12, 18, 14:, 25, f, f, 24;, 28, a, 22, 29, 11, 28, a, 27, w and 26, and thence back through (7) and 17 to c. The generator c at sub-station C is turned until the controllers 8 have returned into their initial position. In this position the ball or roller g of sub-station D again rests on the surface of shaft x and in consequence thereof contact 28 is interrupted and the alarm 'w of station D is cut out.

i' path of'the calling current at the stationv` responding point of the switch or controller of the subscriber calling the other sub-station up, and automatically throwing in the call alarln of the called-up station in the place of the switch or controller at that station. i

'3. The method of Operating a telephone system, which consists in causing all the subscriber switches or controllers with the only eXception of the calling` station to be temporarily stopped by a preliminary operation efi'ected von the corresponding point of the controller of the calling station,` thus causing the alarm on the called-up station to be thrown in until all controllers have returned to their position of rest and utilizing the current serving for Operating the alarm to return all the controllers toV theirl position of rest. z a

4. In a telephone system, in combination, a plurality of sub-stations connected to common lines, a step by step switch or controller V on each sub-station, connections between' each controller and all sub-stations, means for bringing each' controller in connection with a single sub-station and means for automatically changing over the call current at the point of the controller which has been set for a certain station.

5. In a telephone system, in combination, a plurality of sub-stations connected to common lines, a step by step switch or controller 'on each sub-station, connections between each controller and all sub-stations, means for bringing each' controller in connection with asingle sub-station, means for automatically changing over the call current at vthe point of the controller which has been set for a certain station, and means for' preventing the controller from passing beyond the desired position and for automatically interrupting the controller movement and i throwing in the alarm of the desired substation.

6. In a telephone system, in combination, a. plurality of sub-statons connected to common lines, a controller in each sub-station connected with, all sub-stations and means for temporarily retarding the movement of all the controllers excepting the one operated to call up the desired station.

In testimony whereof we aflix our signatures, in presence of two-witnesses.V

WILLI' HERRMANN. `OTTO STRITTER.

lVitnesses w i i HENRY HAsrnR,

ALLEN F. JENNINGSI.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of t'atent s,l

Washington, D. 0. 

